Bending tool and method for reshaping a bone plate

BACKGROUND

This disclosure relates in general to orthopedic surgical devices and procedures, and more particularly, to internal fixation devices, instruments, and methods for the surgical correction of bones or for the repair of fractured bones of a patient.

Orthopedic surgeons are increasingly aware of the importance of properly treating midfoot fractures and dislocations, due partly to the more widespread use of CT and MRI scans. Even apparently simple avulsion fractures may be associated with significant joint damage that may lead to late pain. Since there is relatively little motion in the midfoot, successful fusion of the midfoot joints after fracture does not result in major disability. Therefore, a common surgical option for treating midfoot fractures and dislocations is fixation of adjacent bones using bone plates and/or screws.

Improvements to currently available bone plates for fusing the bones of the midfoot, as well as other bones of the foot, are needed for numerous reasons. For example, currently surgeons must first tightly draw together the bones of the midfoot before fixation with a bone plate. In some situations, it may be difficult for the surgeon to maintain the compression of bones until fixation, thereby resulting in undesirable gaps at the multi-directional, intersecting joint lines between the bones.

The following discloses novel implants, instruments, and methods for orthopedic surgery, which may be used in the bones of the foot or in other anatomies.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

In one form, the present disclosure provides a bending tool for reshaping a bone plate to conform to contours of a bone surface. The bone plate may include a pair of spaced-apart threaded, cylindrical elements removably attached to the bone plate and extending above a top surface of the bone plate. The bending tool may include a handle and a distal head. The distal head may be attached to a distal end of the handle and may include a cavity that is sized and shaped to fit over the pair of spaced-apart threaded, cylindrical elements. A user, while holding the bone plate, may manually apply a leverage force to the bending tool while the cavity of the distal head is fitted over the pair of spaced-apart threaded, cylindrical elements to transmit a sufficient, regionalized bending moment to the bone plate through the pair of threaded, cylindrical elements to reshape the bone plate.

In another form, the present disclosure provides a bending tool set for reshaping a bone plate that has four threaded holes, each of which contains a threaded, cylindrical element removably attached thereto, thereby forming a first pair and a second pair of threaded, cylindrical elements. The bending tool set may include a first bending tool and a second bending tool. The first bending tool may include a first handle and a first distal head attached to a distal end of the first handle. The distal head may include a first cavity sized and shaped to fit closely over the first pair of threaded, cylindrical elements. The second bending tool may include a second handle and a second distal head attached to a distal end of the second handle. The second distal head may include a second cavity sized and shaped to fit closely over the second pair of threaded, cylindrical elements. A user may simultaneously apply an equal and opposite leverage force to each the first and second handles while the first cavity is fitted over the first pair of threaded, cylindrical elements and the second cavity is fitted over the second pair of threaded, cylindrical elements, thereby transmitting a sufficient, regionalized bending moment through the first and second pairs of threaded, cylindrical elements and into the bone plate to bend a region of the bone plate between the first and second pairs of threaded, cylindrical elements.

In yet another form, the present disclosure provides a bending tool for reshaping a bone plate. The bone plate may include a plurality of threaded screw holes and a plurality of drill guides threaded into the screw holes. The bending tool may include a handle and a head on a distal end of the handle. The handle may include a proximal end and a distal end. The head may be adapted to simultaneously engage two of the drill guides such that sufficient manual leverage on the handle transmits a force capable of bending the plate.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE FIGURES

The following description and the accompanying drawings illustrate non-limiting examples of the invention. Unless otherwise indicated, like reference numerals identify the same elements.

<figref idrefs="DRAWINGS">FIG. 1</figref> is a top perspective view of a first bone plate, shown assembled with a plurality of drill guides, for fusion of the dorsal midfoot of the surgical patient.

<figref idrefs="DRAWINGS">FIG. 2</figref> is a dorsal view of the bones of the human foot, showing the first bone plate of <figref idrefs="DRAWINGS">FIG. 1</figref>, (shown without the drill guides for clarity) positioned on the dorsal midfoot.

<figref idrefs="DRAWINGS">FIG. 3A</figref> is a top view of the first bone plate.

<figref idrefs="DRAWINGS">FIG. 3B</figref> is a side view of the first bone plate.

<figref idrefs="DRAWINGS">FIG. 3C</figref> is an end view of the first bone plate.

<figref idrefs="DRAWINGS">FIG. 3D</figref> is a bottom view of the first bone plate.

<figref idrefs="DRAWINGS">FIG. 4</figref> is a perspective view of a locking screw.

<figref idrefs="DRAWINGS">FIG. 5</figref> is a perspective view of a compressing screw.

<figref idrefs="DRAWINGS">FIG. 6</figref> is a top view of the first bone plate partially attached to the bones of the dorsal midfoot using four compressing screws.

<figref idrefs="DRAWINGS">FIG. 7</figref> is a side view of the first bone plate, compressing screws and bones of the dorsal midfoot shown in <figref idrefs="DRAWINGS">FIG. 6</figref>.

<figref idrefs="DRAWINGS">FIG. 8</figref> is a top view of the first bone plate fully attached to the bones of the dorsal midfoot using four compressing screws and four locking screws.

<figref idrefs="DRAWINGS">FIG. 9</figref> is a top perspective view of a bending tool.

<figref idrefs="DRAWINGS">FIG. 10A</figref> is a bottom view of the bending tool of <figref idrefs="DRAWINGS">FIG. 9</figref>.

<figref idrefs="DRAWINGS">FIG. 10B</figref> is a side view of the bending tool of <figref idrefs="DRAWINGS">FIG. 9</figref>.

<figref idrefs="DRAWINGS">FIG. 11</figref> shows an opposing pair of bending tools oriented for placement onto the drill guides preassembled to the first bone plate, which has been initially positioned on the bones of the dorsal midfoot.

<figref idrefs="DRAWINGS">FIG. 12</figref> shows the opposing pair of bending tools placed onto the drill guides preassembled to the first bone plate, such that a user may apply a leverage force to the bending tools to transmit a bending moment to the first bone plate to reshape it about its anterior-posterior axis.

<figref idrefs="DRAWINGS">FIG. 13</figref> is a top perspective view of a second bone plate, shown assembled with a plurality of drill guides, for the fusion of the bones of the medial lateral column of the surgical patient's foot.

<figref idrefs="DRAWINGS">FIG. 14</figref> is a bottom perspective view of the second bone plate of <figref idrefs="DRAWINGS">FIG. 13</figref>, shown assembled with the plurality of drill guides.

<figref idrefs="DRAWINGS">FIG. 15</figref> is a medial view of the human foot <b>10</b> and shows the result of a step of a first fusion method, wherein the user attaches the second bone plate to the navicular tarsal bone by insertion of three locking screws.

<figref idrefs="DRAWINGS">FIG. 16</figref> shows the result of another step of the first fusion method, wherein the user partially attaches the second bone plate to the first cuneiform bone by the insertion of one compressing screw after the step of <figref idrefs="DRAWINGS">FIG. 15</figref>.

<figref idrefs="DRAWINGS">FIG. 17</figref> shows the result of another step of the first fusion method, wherein the user fully attaches the second bone plate to the first cuneiform bone by the insertion of three locking screws after the step of <figref idrefs="DRAWINGS">FIG. 16</figref>.

<figref idrefs="DRAWINGS">FIG. 18</figref> shows the result of another step of the first fusion method, wherein the user partially attaches the second bone plate to the first metatarsal bone by the insertion of one compressing screw after the step of <figref idrefs="DRAWINGS">FIG. 17</figref>.

<figref idrefs="DRAWINGS">FIG. 19</figref> shows the result of another step of the first fusion method, wherein the user fully attaches the second bone plate to the first metatarsal bone by the insertion of three locking screws after the step of <figref idrefs="DRAWINGS">FIG. 18</figref>, thereby completing the fusion of the medial column of the patient's foot.

<figref idrefs="DRAWINGS">FIG. 20</figref> shows the result of a step of a second fusion method, wherein the user partially attaches the second bone plate to the metatarsal by the insertion of one compressing screw after the step of <figref idrefs="DRAWINGS">FIG. 15</figref>.

<figref idrefs="DRAWINGS">FIG. 21</figref> shows the result of a number of steps of the second fusion method, wherein the user completes the attachment of the second bone plate to the bones of the medial column after the step of <figref idrefs="DRAWINGS">FIG. 20</figref>.

DETAILED DESCRIPTION

<figref idrefs="DRAWINGS">FIG. 1</figref> is a top perspective view of a first bone plate <b>40</b>, as it may be provided by the manufacturer, shown preassembled with a plurality of drill guides <b>80</b>. <figref idrefs="DRAWINGS">FIG. 4</figref> shows a compressing screw <b>95</b> and a locking screw <b>93</b>. A dorsal midfoot bone plate system may include first bone plate <b>40</b> preassembled with plurality of drill guides <b>80</b>, a plurality of compressing screws <b>95</b> and a plurality of locking screws <b>93</b>.

<figref idrefs="DRAWINGS">FIG. 2</figref> is a dorsal view of the bones of the human foot <b>10</b>, showing first bone plate <b>40</b> positioned on the dorsal midfoot <b>15</b>. <figref idrefs="DRAWINGS">FIG. 2</figref> also indicates the conventional medical terms, “anterior, posterior, medial, lateral”, as we shall refer to the sides of the human foot <b>10</b>. The bones of the human foot <b>10</b> include the navicular tarsal bone <b>12</b>, the first cuneiform <b>14</b>, the second cuneiform <b>16</b>, the third cuneiform <b>18</b>, the first metatarsal <b>20</b>, the second metatarsal <b>22</b>, the third metatarsal <b>24</b>, the fourth metatarsal <b>26</b>, the fifth metatarsal <b>28</b>, the first phalanges <b>30</b>, the second phalanges <b>32</b>, the third phalanges <b>34</b>, the fourth phalanges <b>36</b> and the fifth phalanges <b>38</b>. The dorsal midfoot <b>15</b> is formed by the convergence of the second cuneiform <b>16</b>, the third cuneiform <b>18</b>, the second metatarsal <b>22</b> and the third metatarsal <b>24</b>.

<figref idrefs="DRAWINGS">FIGS. 3A</figref>, <b>3</b>B, <b>3</b>C and <b>3</b>D are orthogonal views of first bone plate <b>40</b>, which are described next in conjunction with <figref idrefs="DRAWINGS">FIG. 1</figref>. First bone plate <b>40</b> has a frame <b>46</b> that has a quadrilateral shape that defines a window <b>56</b>, a top surface <b>42</b> and a bottom surface <b>44</b> that contacts the bone surfaces after implantation. In this embodiment, frame <b>46</b> has an approximately square shape defining window <b>56</b>. Frame <b>46</b> defines an anterior-posterior axis <b>134</b> (or A-P axis <b>134</b>) and a medial-lateral axis <b>136</b> (or M-L axis <b>136</b>).

Frame <b>46</b> has a first corner <b>48</b> containing a first threaded hole <b>49</b>, a second corner <b>50</b> containing a second threaded hole <b>51</b>, a third corner <b>52</b> containing a third threaded hole <b>53</b>, and a fourth corner <b>54</b> containing a fourth threaded hole <b>55</b>. Each of first, second, third and fourth threaded holes, <b>49</b>, <b>51</b>, <b>53</b> and <b>55</b> may be a tapered, multiple-lead, and internally threaded hole.

As may be viewed most easily in <figref idrefs="DRAWINGS">FIG. 3D</figref>, the thickness of first corner <b>48</b>, second corner <b>50</b>, third corner <b>52</b> and fourth corner <b>54</b> are approximately equal and may be greater than the portions of frame <b>46</b> connecting them to facilitate reshaping of first bone plate <b>40</b> during the surgical procedure.

Each of first, second, third and fourth threaded holes, <b>49</b>, <b>51</b>, <b>53</b> and <b>55</b> respectively, may be preassembled with one of the plurality of drill guides <b>80</b> threaded into the holes, an example of which is disclosed in US20070233112. Each of the plurality of drill guides <b>80</b> facilitate drilling of a properly aligned pilot hole into the bone for receiving a locking screw <b>90</b> shown in <figref idrefs="DRAWINGS">FIG. 4</figref>.

As shown in <figref idrefs="DRAWINGS">FIG. 1</figref>, drill guide <b>80</b>, includes a barrel portion <b>82</b> having a barrel diameter and a barrel length. For the drill guide embodiment shown herein, the barrel diameter may be approximately in the range of 2 mm to 5 mm and barrel length may be approximately in the range of 5 mm to 10 mm. When drill guide <b>80</b> is preassembled to bone plate <b>40</b>, the barrel portion extends above top surface <b>42</b>. Drill guide <b>80</b> has a threaded portion <b>84</b> that threadably engages into any one of the threaded holes <b>49</b>, <b>51</b>, <b>53</b> and <b>55</b>. Drill guide <b>80</b> has a through bore <b>86</b> that is coaxial with the threaded portion and sized to guide the drill bit required to drill the properly sized pilot hole. Drill guide <b>80</b> has a hex-shaped, drive socket <b>88</b> provided for insertion and removal of drill guide <b>80</b> into bone plate <b>40</b>.

Those skilled in the art will recognize that it would also be possible to removably attach any one of numerous other types of threaded, cylindrical elements into any one of threaded holes <b>49</b>, <b>51</b>, <b>53</b> and <b>55</b>. For example, a solid, threaded, cylindrical element such as a short screw with a cylindrical head may be removably attached to a threaded hole. Although such a cylindrical element does not have a through bore for guiding a drill, it may still be used in conjunction with a bending tool, such as the tool shown in <figref idrefs="DRAWINGS">FIG. 47</figref> of US20090118768 to reshape bone plate <b>40</b>.

Locking screw <b>90</b> includes a tapered, multiple-lead, externally threaded head <b>94</b> designed for threadable, locking engagement into any one of threaded holes <b>49</b>, <b>51</b>, <b>53</b> and <b>55</b>. Locking screw has a drive socket <b>93</b>, a threaded shank <b>92</b> for engagement into cortical bone, and a self-tapping tip <b>91</b>. For the embodiment of locking screw <b>90</b> shown herein, threaded shank <b>92</b> may have a major diameter, for example, of 1.25 mm.

Still referring to <figref idrefs="DRAWINGS">FIGS. 1</figref>, <b>3</b>A, <b>3</b>B, <b>3</b>C and <b>3</b>D, first bone plate <b>40</b> further includes a first tab <b>58</b> extending from corner <b>48</b> and containing a first slot <b>59</b> having a first longitudinal axis <b>69</b>, a second tab <b>60</b> extending from corner <b>50</b> and containing a second slot <b>61</b> having a second longitudinal axis <b>71</b>, a third tab <b>62</b> extending from third corner <b>52</b> and containing a third slot <b>63</b> having a longitudinal axis <b>73</b>, and a fourth tab <b>64</b> extending from corner <b>54</b> and containing a fourth slot <b>65</b> having a fourth longitudinal axis <b>75</b>. Each of first longitudinal axis <b>69</b>, second longitudinal axis <b>71</b>, third longitudinal axis <b>73</b> and fourth longitudinal axis <b>75</b> is directed in the plane of frame <b>46</b> and approximately diagonally through window <b>56</b>.

Each of first slot <b>59</b>, second slot <b>61</b>, third slot <b>63</b> and fourth slot <b>63</b> may receive a compressing screw <b>95</b>, which is shown in <figref idrefs="DRAWINGS">FIG. 5</figref>. As will be described, compressing screw <b>95</b> may be used to move bone parts together prior to inserting additional locking screws to complete attachment of the bone plate to the bone parts. Compressing screw <b>95</b> may be formed from a variety of metal alloys, such as Ti 6A1-4V, and includes a smooth conical head <b>99</b> having a drive socket <b>98</b>, a threaded shank <b>97</b> for engagement into cortical bone, and a self-tapping tip <b>96</b>. Threaded shank <b>97</b> may, for example, have a major diameter of 1.25 mm.

First bone plate <b>40</b> may be formed from a titanium alloy, a stainless steel or any one of a number of biocompatible materials well-known in the art. The manufacturing processes for forming first bone plate <b>40</b> are also well-known, although the exact processes may vary to provide desired mechanical properties such as the ability to be reshaped during the surgical procedure to conform to the bone surfaces.

The user may attach first bone plate <b>40</b> onto the bones of the dorsal midfoot <b>15</b> as described next in conjunction with <figref idrefs="DRAWINGS">FIGS. 6</figref>, <b>7</b> and <b>8</b>. <figref idrefs="DRAWINGS">FIG. 6</figref> is a top view and <figref idrefs="DRAWINGS">FIG. 7</figref> is a side view showing first bone plate <b>40</b> partially attached to the bones of the dorsal midfoot <b>15</b> using four compressing screws <b>95</b>. One compressing screw <b>95</b> passes through first slot <b>59</b> and threadably engages into the second cuneiform <b>16</b>; one compressing screw <b>95</b> passes through second slot <b>61</b> and threadably engages into the second metatarsal <b>22</b>; one compressing screw <b>95</b> passes through third slot <b>63</b> and threadably engages into the third cuneiform <b>18</b>; one compressing screw <b>95</b> passes through fourth slot <b>65</b> and threadably engages into the third metatarsal <b>24</b>.

To achieve the result shown in <figref idrefs="DRAWINGS">FIGS. 6 and 7</figref>, the user may first make an incision over the bones of the dorsal midfoot <b>15</b>, retract the soft tissues and then place first bone plate <b>40</b> onto the dorsal midfoot <b>15</b>, such that window <b>56</b> approximately centers over the junction of the four bones of the dorsal midfoot <b>15</b>. The user may choose to reshape first bone plate <b>40</b> (as will be described later for <figref idrefs="DRAWINGS">FIGS. 11 and 12</figref>) until first bone plate <b>40</b> conforms closely to the contours of the surfaces of the bones. To insure good screw engagement into bone and implantation of a robust construct, the user may position first tab <b>58</b> over the second cuneiform <b>12</b>, second tab <b>60</b> over the second metatarsal <b>22</b>, third tab <b>62</b> over the third cuneiform <b>18</b> and fourth tab <b>64</b> over the third metatarsal <b>24</b>.

Next, one at a time, the user may drill each pilot hole and then partially insert each compressing screw <b>95</b> until all four compressing screws are partially engaged into the four bones of the dorsal midfoot <b>15</b>. The user may then gradually tighten each of the four compressing screws <b>95</b> alternately until each is snuggly engaged into the underlying bone. Each of first slot <b>59</b>, second slot <b>61</b>, third slot <b>63</b> and fourth slot <b>65</b> are oriented diagonally as described for <figref idrefs="DRAWINGS">FIG. 3A</figref>, such that fully inserting each compressing screw <b>95</b> in the respective slot urges movement of the attached underlying bone approximately inwardly against the other three bones of the dorsal midfoot <b>15</b>. Therefore, upon full insertion of the four compressing screws <b>95</b>, the four bones of the dorsal midfoot <b>15</b> are dynamically compressed inwardly together, simultaneously in both the anterior-posterior direction and the medial-lateral direction. This type of compression, also referred to as “multi-axial compression”, as opposed to axial compression provided by previous bone plates, helps the user to achieve minimal spacing between the four bone parts so that the bone parts may fuse together. Those skilled in the art will now envision other possible types of bone plates incorporating multi-axial compression for drawing together multiple bone parts of various types, including whole bones and bone fragments of fractured bones.

Once the four compressing screws <b>95</b> are fully inserted, the user may drill four pilot holes and insert four locking screws <b>90</b> as shown in <figref idrefs="DRAWINGS">FIG. 8</figref>, thereby completing the fusion of the bones of the dorsal midfoot <b>15</b>.

For clarity, <figref idrefs="DRAWINGS">FIGS. 6 and 7</figref> do not show the first plurality of drill guides <b>80</b> preassembled into first bone plate <b>40</b>, such as is shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. Clearly, it is possible to use a handheld drill guide to drill each of the pilot holes for the four locking screws <b>90</b>. However, preassembled drill guides <b>80</b> as shown in <figref idrefs="DRAWINGS">FIG. 2</figref> provides numerous advantages. One advantage is that providing the first plurality of drill guides <b>80</b> preassembled to first bone plate <b>40</b> enables the user to reshape first bone plate <b>40</b> in vivo, as will be described next.

The method just described is one of a number of possible method embodiments for attaching first bone plate <b>40</b> to the bones of the dorsal midfoot. For example, in an alternate method embodiment, the user may prepare the surgical site and position first bone plate <b>40</b> on the bones of the dorsal midfoot as previously described. Next the user may fully insert a pair of compressing screws <b>95</b> on one side of plate <b>40</b> and then fully insert a pair of locking screws <b>90</b> on the same side of plate <b>40</b>. Next the user may fully insert a pair of compressing screws <b>95</b> on the opposite side of plate <b>40</b> and then fully insert a pair of locking screws <b>90</b> on that side of plate <b>40</b>.

<figref idrefs="DRAWINGS">FIG. 9</figref> is a top perspective view, <figref idrefs="DRAWINGS">FIG. 10A</figref> is a bottom view and <figref idrefs="DRAWINGS">FIG. 10B</figref> is a side view of a first bone plate bending tool <b>100</b> that includes a distal end <b>102</b>, a proximal end <b>104</b> and a longitudinal axis <b>116</b> extending therebetween. First bending tool <b>100</b> further includes a distal head <b>108</b> that is attached to distal end <b>102</b> of a handle <b>106</b>. Distal head <b>108</b> has a cavity <b>110</b> sized and shaped to fit over a pair of adjacent drill guides <b>80</b>, wherein the axes defined by bore <b>86</b> of each drill guide <b>80</b> are approximately parallel.

As labeled in <figref idrefs="DRAWINGS">FIG. 9</figref>, cavity <b>100</b> has a cavity length (CL), a cavity width (CW) and a cavity depth (CD). The cavity width is slightly greater than the barrel diameter of drill guide <b>80</b>. The cavity length is greater than the sum of twice the barrel diameter and the separation distance between the adjacent drill guides <b>80</b>. The cavity depth may be, for example, at least half of the barrel length of drill guide <b>80</b> to provide ample engagement of cavity <b>100</b> to the adjacent pair of drill guides <b>80</b> to transmit a high leverage force without slipping apart. To insure maximum engagement, the cavity depth may be equal to or greater than the barrel length. The cavity may shaped to engage the drill guides <b>80</b> at a separation distance between the drill guides <b>80</b> of between approximately 5 mm and 25 mm, of example.

A bone tool set may include a second bending tool <b>100</b>′ that is identical to first bending tool <b>100</b>. <figref idrefs="DRAWINGS">FIGS. 11 and 12</figref> depict how the user may use bending tool set <b>101</b> to reshape first bone plate <b>40</b> about AP axis <b>134</b>. First bending tool <b>100</b> may be be fitted over a first pair <b>81</b> of drill guides <b>80</b>, and second bending tool <b>100</b>′ may be fitted over a second pair <b>83</b> of drill guides <b>80</b>, wherein the first pair <b>81</b> and second pair <b>83</b> are preassembled to bone plate <b>40</b> on opposing sides of the region of bone plate <b>40</b> to be bent. As shown in <figref idrefs="DRAWINGS">FIG. 12</figref>, first pair <b>81</b> defines a first pair axis <b>85</b> and second pair <b>83</b> defines a second pair axis <b>87</b>, which is approximately parallel to first pair axis <b>85</b>.

As shown in <figref idrefs="DRAWINGS">FIG. 12</figref> and indicated by arrows, the user may apply a leverage force to bending tool <b>100</b> in a direction that is approximately perpendicular to first pair axis <b>85</b> and an equal and opposite leverage force to bending tool <b>100</b>′ in a direction that is approximately perpendicular to second pair axis <b>87</b>. In this way, the user may controllably transmit a sufficient bending moment into the region of bone plate <b>40</b> between first pair <b>81</b> and second pair <b>83</b> to bend bone plate <b>40</b> about A-P axis <b>134</b>, thereby reshaping bone plate <b>40</b> to conform more closely to the contours of the underlying bone surfaces. Alternately, the user may use bending tool set <b>101</b> to bend first bone plate <b>40</b> about M-L axis <b>136</b>, in which case, first pair <b>81</b> would include the two drill guides <b>80</b> anterior to M-L axis <b>136</b> and second pair <b>83</b> would include the two drill guides <b>80</b> posterior to M-L axis <b>134</b>.

Tool <b>100</b> and second tool <b>100</b>′ may be used to reshape bone plate <b>40</b> already positioned onto the bone site as shown in <figref idrefs="DRAWINGS">FIGS. 11 and 12</figref>, or may be used to reshape bone plate <b>40</b> outside of the patient's body. The user may use the pair of tools <b>100</b>, <b>100</b>′ to bend first bone plate <b>40</b> about the A-P axis <b>134</b>, as shown in <figref idrefs="DRAWINGS">FIGS. 11 and 12</figref>.

In some situations, it may also be possible for the user to apply a leverage force to first bending tool <b>100</b> fitted over first pair <b>81</b> of drill guides <b>80</b>, while holding bone plate <b>40</b> by hand or against a relatively immovable, sterile surface, for example.

Using bending tool set <b>101</b> enables the user to apply a regionalized bending moment to the bone plate. This may reduce the number of tool applications required to reshape the bone plate, reduce surgical time, and help create a desired, uniform bend about an axis of the bone plate. In addition, using each bending tool to apply the leverage force to a pair of adjacent drill guides (or other types of cylindrical elements inserted into the threaded holes, as noted earlier). Compared to engagement with a single drill guide, by applying force to more than one drill guide the stress magnitude is significantly reduced at the threaded engagement between each drill guide and corresponding threaded hole. This may allow the user to apply much greater leverage force to the bending tools, so that it is possible to bend significantly stiffer bone plates.

Bending tool <b>100</b> may further include a proximal end effector <b>112</b> and a proximal post <b>114</b>. Distal end <b>102</b> defines a distal axis <b>118</b> that may form an angle “A” with longitudinal axis <b>116</b>. Proximal end <b>104</b> defines a proximal axis <b>120</b> that may form an angle “B” with longitudinal axis <b>116</b>. The angles “A” and “B” facilitate access and visualization to the surgical wound site during use and the ergonomic application of hand force. Tool <b>100</b> may be formed from a stainless steel or any one of many other rigid, biocompatible materials that are commonly used for surgical instruments.

Still referring to <figref idrefs="DRAWINGS">FIGS. 9</figref>, <b>10</b>A and <b>10</b>B, proximal end effector <b>112</b> of tool <b>100</b> may include a slot <b>113</b> that is sized and shaped to fit closely over the thickness of first bone plate <b>40</b>. Similarly, tool <b>100</b>′ includes a similar, proximal end effector and slot, such that the pair of tools <b>100</b>, <b>100</b>′ may also be used like a pair of conventional, surgical bending irons that are well-known in the art.

Post <b>114</b> is sized and shaped to fit into the bore of drill guide <b>80</b>, thereby enabling the user another way to apply force individually to any one of drill guides preassembled to first bone plate <b>40</b>. Using post <b>114</b> of tool <b>100</b> in opposition to tool <b>100</b>′ having a post <b>114</b>′ (not shown) enables the user to apply a directed bending force to first bone plate <b>40</b>, such as may be useful for “tweaking” the final, desired shape of first bone plate <b>40</b>.

Proximal end effector <b>112</b> and post <b>114</b> also enable the user to use tool <b>100</b> on other bone plates that are preassembled with drill guides <b>80</b>, but that do not have a pair of drill guides properly spaced for use with distal head <b>108</b>.

<figref idrefs="DRAWINGS">FIG. 13</figref> is a top perspective view and <figref idrefs="DRAWINGS">FIG. 14</figref> is a bottom perspective view of a second bone plate <b>120</b>, shown preassembled with a plurality of drill guides <b>80</b>. A medial column fusion system for fusing the bones of the medial column (inside) of the surgical patient's foot includes second bone plate <b>120</b> that is preassembled with plurality of drill guides <b>80</b>, a plurality of compressing screws <b>95</b> and a plurality of locking screws <b>93</b>.

<figref idrefs="DRAWINGS">FIG. 15</figref> shows the result of a step of a first fusion method and illustrates the positioning of second bone plate <b>120</b> on the medial column <b>17</b> of foot <b>10</b>. The medial column <b>17</b> is formed by a series of three bones of the inner foot: the navicular tarsal <b>12</b>, the first cuneiform <b>14</b> and the first metatarsal <b>20</b>.

As shown in <figref idrefs="DRAWINGS">FIGS. 13 and 14</figref>, second bone plate <b>120</b> has a generally elongated shape defining a longitudinal axis <b>125</b>, a top surface <b>130</b> and a bottom surface <b>132</b> for contact against the underlying bones of the medial column <b>17</b>. Second bone plate <b>120</b> includes a body element <b>122</b> and an arm element <b>119</b> extending from body element <b>122</b>. Arm element <b>119</b> and body element <b>122</b> extend nearly parallel to each other along opposite sides of longitudinal axis <b>125</b>. A first span element <b>121</b> and a second span element <b>123</b> bridge between arm element <b>119</b> and body element <b>122</b>.

As shown in <figref idrefs="DRAWINGS">FIG. 13</figref>, second bone plate <b>120</b> has three longitudinal portions that correspond to the underlying bones to which they are to be attached: a tarsal portion <b>124</b>, a cuneiform portion <b>126</b> and a metatarsal portion <b>128</b>. A first tab <b>131</b> extends transversely from tarsal portion <b>124</b> and a second tab <b>133</b> extends transversely from metatarsal portion <b>128</b>. As shown in <figref idrefs="DRAWINGS">FIG. 14</figref>, portions of arm element <b>119</b>, body element <b>122</b>, first span <b>121</b>, second span <b>123</b>, first tab <b>131</b> and second tab <b>133</b> have a smaller thickness than the thickness of the rest of second bone plate <b>120</b> to facilitate bending in those regions for reshaping second bone plate <b>120</b> to conform to the contours of the underlying bone surfaces.

Second bone plate <b>120</b> includes a plurality of threaded holes <b>138</b>, each of which may be identical to threaded holes <b>49</b>, <b>51</b>, <b>53</b> and <b>55</b> of first bone plate <b>40</b> (<figref idrefs="DRAWINGS">FIG. 1</figref>). Each of tarsal portion <b>124</b>, cuneiform portion <b>126</b> and metatarsal portion <b>128</b> may include at least one threaded hole <b>138</b> preassembled with drill guide <b>80</b>, although for the embodiment shown in <figref idrefs="DRAWINGS">FIGS. 13 and 14</figref>, each portion has three threaded holes preassembled with three drill guides <b>80</b>. Cuneiform portion <b>126</b> also includes a first slot <b>127</b> and metatarsal portion <b>128</b> also includes a second slot <b>129</b>. First slot <b>127</b> and second slot <b>129</b> may be identical to slots <b>59</b>, <b>61</b>, <b>63</b> and <b>65</b> of first bone plate <b>40</b> and may be used with compressing screw <b>95</b> (<figref idrefs="DRAWINGS">FIG. 5</figref>). First slot <b>127</b> and second slot <b>129</b> are configured and oriented to provide axial compression in a direction towards tarsal portion <b>124</b> and approximately parallel to longitudinal axis <b>125</b>.

Drill guides <b>80</b> provide for drilling coaxially aligned pilot holes for bone screws into the bone. The user also may use drill guides <b>80</b> in combination with one or an opposing pair of bending tools, such as first bending tools <b>100</b> and second bending tool <b>100</b>′, to reshape bone plate <b>120</b>. As previously noted, the user may insert post <b>114</b> of first and second bending tools <b>100</b>, <b>100</b>′ into bore <b>86</b> of drill guides <b>80</b> and apply a leverage force to transmit a bending moment into bone plate <b>120</b>. It is also possible to use other types of bending tools, including without limitation bending irons that engage a single drill guide or bending tools that directly engage the plate.

As described previously for first bone plate <b>40</b>, second bone plate <b>120</b> may be formed from a variety of metal alloys, such as Ti 6A1-4V, or any one of a number of biocompatible materials commonly used for the construction of bone plates using conventional manufacturing techniques, although some variations of manufacturing techniques may be employed to provide specific mechanical properties.

Two surgical methods are described next for fusing the bones of the medial column of the foot using the medial column fusion system. In a first fusion method, the navicular tarsal <b>12</b> and the first cuneiform <b>14</b> are first drawn together and then the first metatarsal <b>20</b> is drawn against the first cuneiform <b>14</b>. In a second fusion method, the navicular tarsal <b>12</b> and the first metatarsal <b>20</b> are drawn together while the first cuneiform <b>14</b> is permitted to move with the first metatarsal <b>20</b>.

<figref idrefs="DRAWINGS">FIGS. 15-19</figref> depict the results of steps included in the first fusion method. <figref idrefs="DRAWINGS">FIGS. 15</figref>, <b>20</b> and <b>21</b> depict the results of steps included in the second fusion method.

<figref idrefs="DRAWINGS">FIGS. 15-21</figref> show second bone plate <b>40</b> without preassembled drill guides <b>80</b>. For the steps of the first and second fusion methods described next, it should be understood that insertion of locking screw <b>90</b> includes drilling a pilot hole into bone with either drill guide <b>80</b> preassembled to second bone plate <b>120</b>, a conventional handheld drill guide or without any type of drill guide, although the latter is likely to result in binding of the screw being inserted if the pilot hole in the bone is not coaxial with the threaded hole of the plate. However, providing second bone plate <b>120</b> with preassembled drill guides <b>80</b> enables the user to perform the surgical procedure more quickly and more accurately than if using a handheld drill guide and also provides the ability to reshape the bone plate using bone shaping tools as previously described. When using second bone plate <b>120</b> with preassembled drill guides <b>80</b>, each drill guide <b>80</b> should be removed from second bone plate <b>120</b> after drilling the pilot hole.

Similarly, for the steps of the first and second fusion methods described next, it should be understood that insertion of compressing screw <b>95</b> includes drilling a pilot hole into bone.

The first steps for both the first and second fusion methods include incising the soft tissues overlying the medial column <b>17</b> of the foot <b>10</b> and retracting the soft tissues to expose the bones of the medial column.

The next step of both the first and second fusion methods is depicted in <figref idrefs="DRAWINGS">FIG. 15</figref> in which the user attaches second bone plate <b>120</b> to the navicular tarsal <b>12</b>. The user inserts at least one locking screw <b>94</b> through tarsal portion <b>124</b> of second bone plate <b>120</b> and into the navicular tarsal <b>12</b>, although for this embodiment of second bone plate <b>120</b>, the user may insert up to three locking screws <b>94</b> through tarsal portion <b>124</b> and into the navicular tarsal <b>12</b>.

The remaining steps of the first fusion method include the following: The user partially attaches second bone plate <b>120</b> to the first cuneiform <b>14</b> by the insertion of one compressing screw <b>95</b> through first slot <b>127</b> of cuneiform portion <b>126</b> of second bone plate <b>140</b> and into the underlying cuneiform <b>14</b> (<figref idrefs="DRAWINGS">FIG. 16</figref>). This step axially compresses cuneiform <b>14</b> against navicular tarsal <b>12</b>. Then the user inserts at least one locking screw <b>90</b> through cuneiform portion <b>127</b> of second bone plate <b>120</b> and into cuneiform <b>14</b>, although for this embodiment of second bone plate <b>120</b>, the user may insert up to three locking screws <b>90</b> (<figref idrefs="DRAWINGS">FIG. 17</figref>) through cuneiform portion <b>126</b>. Next the user inserts compressing screw <b>95</b> through second slot <b>129</b> of metatarsal portion <b>128</b> of second bone plate <b>120</b> and into the metatarsal <b>20</b> (<figref idrefs="DRAWINGS">FIG. 18</figref>). This step axially compresses the metatarsal <b>20</b> against the cuneiform <b>14</b>. Next the user completes the fusion of medial column <b>17</b> by inserting at least one locking screw <b>90</b> through metatarsal portion <b>128</b> of second bone plate <b>120</b> and into the metatarsal <b>20</b> (<figref idrefs="DRAWINGS">FIG. 19</figref>), although for this embodiment the user may insert up to three locking screws <b>90</b> through metatarsal portion <b>128</b>.

The remaining steps of the second fusion method (after performing the step depicted in <figref idrefs="DRAWINGS">FIG. 15</figref>) include the following: The user inserts compressing screw <b>95</b> through second slot <b>129</b> of second bone plate <b>120</b> and into the metatarsal <b>20</b> (<figref idrefs="DRAWINGS">FIG. 20</figref>). The user then inserts at least one locking screw <b>90</b> through metatarsal portion <b>128</b> of second bone plate <b>120</b> and into the metatarsal <b>20</b>. For this embodiment, the user may insert up to three locking screws <b>90</b> through metatarsal portion <b>128</b> (<figref idrefs="DRAWINGS">FIG. 21</figref>). Next the user inserts compressing screw <b>95</b> through slot <b>127</b> of cuneiform portion <b>126</b> and into cuneiform <b>14</b>. For this step, the user may choose to insert compressing screw <b>95</b> into a “neutral”, central portion of slot <b>127</b>, such that the head of screw <b>95</b> does not forcefully interact with slot <b>127</b>. This is because the desired compression of the bones was already achieved by the insertion of compressing screw <b>95</b> in second slot <b>129</b>. Finally, the user inserts at least one locking screw <b>90</b> through cuneiform portion <b>126</b> of second bone plate <b>120</b> and into the cuneiform <b>14</b>, although for this embodiment the user may insert up to three locking screws <b>90</b> through cuneiform portion <b>126</b>.

For both the first and second fusion methods, after the user has completed the attachment of second bone plate <b>120</b> to the medial column <b>17</b>, the user finally closes the incision using conventional techniques for this type of surgical procedure.

Having shown and described various embodiments and examples of the present invention, further adaptations of the methods and devices described herein can be accomplished by appropriate modifications by one of ordinary skill in the art without departing from the scope of the present invention. Several of such potential modifications have been mentioned, and others will be apparent to those skilled in the art. For example, the specific materials, dimensions, and the scale of drawings will be understood to be non-limiting examples. As a further example, the foregoing disclosure included many example of foot anatomy, but the teachings of this disclosure may also be used for bones of other anatomies. Accordingly, the scope of the present invention should be considered in terms of the following claims and is understood not to be limited to the details of structure, materials, or acts shown and described in the specification and drawings.